It is known that certain chemically active metals or reactant metals held as a liquid at elevated temperatures have the ability to chemically reduce organic compounds. Suitable reactant metals include aluminum, magnesium, lithium, and alloys of these metals as described in U.S. Pat. Nos. 5,000,101, 6,069,290, and 6,355,857 to Wagner. The entire content of each of these prior patents is hereby incorporated in this disclosure by this reference. These liquid reactant metals chemically reduce organic molecules to produce mostly hydrogen and nitrogen gas, elemental carbon, char, and metal salts. Most metals mixed with the organic materials or bound up in organic molecules in the waste materials dissolve or melt into the liquid reactant metal. Low boiling point metals such as Mercury may go to a gaseous state and separate from the liquid reactant metal along with other gases. Other metals alloy with the liquid reactant metal or separate from the liquid reactant metal by gravity separation. Liquid reactant metals are also useful in treating radioactive wastes and mixed radioactive and nonradioactive wastes. U.S. Pat. No. 6,355,857 discloses processes for treating radioactive and mixed radioactive and nonradioactive wastes in a liquid reactant metal reactor. Many of the materials in the waste are chemically reduced to produce relatively innocuous compounds or constituent elements. Radioactive metals such as Uranium and transuranic metals are dissolved or otherwise dispersed into the liquid reactant metal. As shown in U.S. Pat. No. 6,355,857 and U.S. patent application Ser. No. 10/059,808, the entire content of which is incorporated by reference, radiation absorbing metals and radiation moderating metals may be included in the liquid reactant metal. The liquid reactant metal, trapped radioactive isotopes, and radiation absorbing or moderating materials may be solidified to form an ingot. In the resulting ingot the radiation absorbing materials absorb radioactive emissions from the trapped radioactive isotopes and greatly reduce the amount of radiation escaping from the ingot. Thus, the ingot provides a good vehicle for the relatively safe, long-term storage of radioactive isotopes.
The liquid reactant metal treatment processes described above and in U.S. Pat. No. 6,355,857 and application Ser. No. 10/059,808 provide ways to effectively isolate radioactive isotopes from mixed non-radioactive and radioactive wastes and effectively store radioactive materials. There remains a need, however, for improved systems for providing the necessary contact between the material to be treated and the reactant metal, and for handling the resulting reaction products. The need is particularly acute for high-level nuclear waste materials such as spent nuclear fuel rods.